Disposable vent lines with reusable monitors for fabricating molded workpiece

Abstract

A molded workpiece is formed using a mold having an inner cavity, an injection port which communicates with the inner cavity for permitting molding material to be injected into the inner cavity, and at least one disposable vent line. The vent line has sidewalls which are substantially transparent to light and provides for venting gases from the inner cavity as molding material is injected into the cavity. A material injector is coupled to the injection port for injecting molding material into the inner cavity through the injection port. A removably sensor receives the disposable vent line for detecting when molding material has substantially filled the vent line and for generating a first signal indicating that the vent line is substantially filled. The sensor includes an infrared light emitting diode positioned adjacent to the vent line for radiating light toward the vent line, and a phototransistor for detecting light radiated through the transparent sidewalls of the vent line and for generating the first signal when no light is detected.

What is claimed is: 
     
       1. An apparatus for forming a molded workpiece comprising: a mold having an inner cavity, injection port means communicating with said inner cavity for permitting molding material to be injected into said inner cavity, and at least first and second disposable vent lines communicating with said inner cavity for allowing gases from said inner cavity to be vented therefrom as said molding material is injected into said inner cavity, said disposable vent lines having sidewalls which are substantially transparent to light;   material injector means for injecting molding material into said inner cavity via said injection port means;   a first sensor receiving said first disposable vent line therethrough and comprising first light emitting means and first light detector means positioned on opposite sides of said first disposable vent line, said first sensor detecting when molding material has substantially filled said first disposable vent line and generating a first fill signal representative thereof when said first light detector means fails to receive light emitted from said first light emitting means through said sidewalls of said first disposable vent line; and   a second sensor receiving said second disposable vent line therethrough and comprising second light emitting means and second light detector means positioned on opposite sides of said second disposable vent line, said second sensor detecting when molding material has substantially filled said second disposable vent line and generating a second fill signal representative thereof when said second light detector means fails to receive light emitted from said second light emitting means through said sidewalls of said second disposable vent line.   
     
     
       2. An apparatus as set forth in claim 1, further including: first visual indicator means responsive to said first signal for indicating that said first disposable vent line is substantially filled with molding material;   second visual indicator means responsive to said second fill signal for indicating that said second disposable vent line is substantially filled with molding material;   third visual indicator means responsive to a third signal generated by said first sensor when said first light detector means receives light emitted from said first light emitting means through said sidewalls of said first disposable vent line for indicating that said inner cavity is not substantially filled with molding material; and,   fourth visual indicator means responsive to a fourth signal generated by said second sensor when said second light detector means receives light emitted from said second light emitting means through said sidewalls of said second disposable vent line for indicating that said inner cavity is not substantially filled with molding material.   
     
     
       3. An apparatus as set forth in claim 2 wherein said first and second visual indicator means comprise red light emitting didoes, and said third and fourth visual indicator means comprise green light emitting diodes. 
     
     
       4. An apparatus for forming a molded workpiece comprising: a mold having an inner cavity, injection port means communicating with said inner cavity for permitting molding material to be injected into said inner cavity, and at least first and second disposable vent lines communicating with said inner cavity for allowing gases from said inner cavity to be vented therefrom as said molding material is injected into said inner cavity, said disposable vent lines having sidewalls which are substantially transparent to light;   material injector means for injecting molding material into said inner cavity via said injection port means;   a first fill sensor removably positioned about said first disposable vent line for generating signals representative of the fill state of a portion of said mold adjacent to said first disposable vent line;   a first fill state circuit coupled to said first fill sensor for visually indicating the fill state of said portion of said mold adjacent to said first disposable vent line;   a second fill sensor removably positioned about said second disposable vent line for generating signals representative of the fill state of a portion of said mold adjacent to said second disposable vent line; and   a second fill state circuit coupled to said second fill sensor for visually indicating the fill state of said portion of said mold adjacent to said second disposable vent line.   
     
     
       5. An apparatus as set forth in claim 4 wherein said first and second fill sensors each comprise: a light emitting diode positioned to emit light toward a disposable vent line received in said fill state sensor; and   a light detecting transistor positioned substantially opposite to said light emitting diode for receiving light passing through said disposable vent line received in said fill state sensor.   
     
     
       6. An apparatus as set forth in claim 5 wherein said light detecting transistor comprises a light activated base, an emitter connected to ground potential and a collector coupled to supply voltage. 
     
     
       7. An apparatus as set forth in claim 6 wherein said first and second fill state circuits each comprise: a state transistor having an emitter connected to ground potential, a collector coupled to supply voltage and a base coupled to the collector of said light detecting transistor;   a first light emitting diode having its anode connected to the collector of said state transistor and its cathode connected to the collector of said light detecting transistor; and   a second light emitting diode having its cathode connected to the collector of said state transistor and its anode connected to the collector of said light detecting transistor.   
     
     
       8. An apparatus as set forth in claim 7 wherein said first light emitting diode emits green light visually indicating that its associated disposable vent line is not filled with molding material. 
     
     
       9. An apparatus as set forth in claim 8 wherein said second light emitting diode emits red light visually indicating that its associated disposable vent line is filled with molding material.